It is well known to couple Time of Flight (“ToF”) mass spectrometry (“MS”) with ion mobility separation (“IMS”) to produce multi-dimensional mass to charge ratio-ion mobility drift time-intensity data. The inherent speed of time of flight separation allows nested data sets to be acquired in which several full mass spectra are produced during the elution time of each ion mobility peak.
As ion mobility separation is somewhat orthogonal to mass separation this can increase peak capacity. For example, ions having the same mass to charge ratio (m/z) (or ions having sufficiently similar mass to charge ratios that they are partially or completely unresolved in the mass to charge ratio dimension) but with different ion mobilities may be separated in the ion mobility dimension. Processing of the data can remove mass interferences, leading to more accurate mass assignment and improved detection limits.
FIG. 6 of US 2013/234016 (Micromass) discloses a mass spectrometer having an ion mobility separation device 2 and a quadrupole filter 8.
It is desired to provide an improved method of mass spectrometry.